/*
* Copyright (c) 2000 Apple Computer, Inc. All rights reserved.
*
* @APPLE_LICENSE_HEADER_START@
*
* Copyright (c) 1999-2003 Apple Computer, Inc. All Rights Reserved.
*
* This file contains Original Code and/or Modifications of Original Code
* as defined in and that are subject to the Apple Public Source License
* Version 2.0 (the 'License'). You may not use this file except in
* compliance with the License. Please obtain a copy of the License at
* http://www.opensource.apple.com/apsl/ and read it before using this
* file.
*
* The Original Code and all software distributed under the License are
* distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
* EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
* INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
* Please see the License for the specific language governing rights and
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*
* @APPLE_LICENSE_HEADER_END@
*/
#ifndef_MACHO_LOADER_H_
#define_MACHO_LOADER_H_/*
* This file describes the format of mach object files.
*//*
* <mach/machine.h> is needed here for the cpu_type_t and cpu_subtype_t types
* and contains the constants for the possible values of these types.
*/
#include<mach/machine.h>/*
* <mach/vm_prot.h> is needed here for the vm_prot_t type and contains the
* constants that are or'ed together for the possible values of this type.
*/
#include<mach/vm_prot.h>/*
* <machine/thread_status.h> is expected to define the flavors of the thread
* states and the structures of those flavors for each machine.
*/
#include<mach/machine/thread_status.h>/*
* The mach header appears at the very beginning of the object file.
*/struct mach_header {
unsignedlong magic; /* mach magic number identifier */
cpu_type_t cputype; /* cpu specifier */
cpu_subtype_t cpusubtype; /* machine specifier */unsignedlong filetype; /* type of file */unsignedlong ncmds; /* number of load commands */unsignedlong sizeofcmds; /* the size of all the load commands */unsignedlong flags; /* flags */
};
/* Constant for the magic field of the mach_header */
#defineMH_MAGIC 0xfeedface /* the mach magic number */
#defineMH_CIGAM NXSwapInt(MH_MAGIC)
/*
* The layout of the file depends on the filetype. For all but the MH_OBJECT
* file type the segments are padded out and aligned on a segment alignment
* boundary for efficient demand pageing. The MH_EXECUTE, MH_FVMLIB, MH_DYLIB,
* MH_DYLINKER and MH_BUNDLE file types also have the headers included as part
* of their first segment.
*
* The file type MH_OBJECT is a compact format intended as output of the
* assembler and input (and possibly output) of the link editor (the .o
* format). All sections are in one unnamed segment with no segment padding.
* This format is used as an executable format when the file is so small the
* segment padding greatly increases it's size.
*
* The file type MH_PRELOAD is an executable format intended for things that
* not executed under the kernel (proms, stand alones, kernels, etc). The
* format can be executed under the kernel but may demand paged it and not
* preload it before execution.
*
* A core file is in MH_CORE format and can be any in an arbritray legal
* Mach-O file.
*
* Constants for the filetype field of the mach_header
*/
#defineMH_OBJECT 0x1 /* relocatable object file */
#defineMH_EXECUTE 0x2 /* demand paged executable file */
#defineMH_FVMLIB 0x3 /* fixed VM shared library file */
#defineMH_CORE 0x4 /* core file */
#defineMH_PRELOAD 0x5 /* preloaded executable file */
#defineMH_DYLIB 0x6 /* dynamicly bound shared library file*/
#defineMH_DYLINKER 0x7 /* dynamic link editor */
#defineMH_BUNDLE 0x8 /* dynamicly bound bundle file *//* Constants for the flags field of the mach_header */
#defineMH_NOUNDEFS 0x1 /* the object file has no undefined
references, can be executed */
#defineMH_INCRLINK 0x2 /* the object file is the output of an
incremental link against a base file
and can't be link edited again */
#defineMH_DYLDLINK 0x4 /* the object file is input for the
dynamic linker and can't be staticly
link edited again */
#defineMH_BINDATLOAD 0x8 /* the object file's undefined
references are bound by the dynamic
linker when loaded. */
#defineMH_PREBOUND 0x10 /* the file has it's dynamic undefined
references prebound. *//*
* The load commands directly follow the mach_header. The total size of all
* of the commands is given by the sizeofcmds field in the mach_header. All
* load commands must have as their first two fields cmd and cmdsize. The cmd
* field is filled in with a constant for that command type. Each command type
* has a structure specifically for it. The cmdsize field is the size in bytes
* of the particular load command structure plus anything that follows it that
* is a part of the load command (i.e. section structures, strings, etc.). To
* advance to the next load command the cmdsize can be added to the offset or
* pointer of the current load command. The cmdsize MUST be a multiple of
* sizeof(long) (this is forever the maximum alignment of any load commands).
* The padded bytes must be zero. All tables in the object file must also
* follow these rules so the file can be memory mapped. Otherwise the pointers
* to these tables will not work well or at all on some machines. With all
* padding zeroed like objects will compare byte for byte.
*/struct load_command {
unsignedlong cmd; /* type of load command */unsignedlong cmdsize; /* total size of command in bytes */
};
/* Constants for the cmd field of all load commands, the type */
#defineLC_SEGMENT 0x1 /* segment of this file to be mapped */
#defineLC_SYMTAB 0x2 /* link-edit stab symbol table info */
#defineLC_SYMSEG 0x3 /* link-edit gdb symbol table info (obsolete) */
#defineLC_THREAD 0x4 /* thread */
#defineLC_UNIXTHREAD 0x5 /* unix thread (includes a stack) */
#defineLC_LOADFVMLIB 0x6 /* load a specified fixed VM shared library */
#defineLC_IDFVMLIB 0x7 /* fixed VM shared library identification */
#defineLC_IDENT 0x8 /* object identification info (obsolete) */
#defineLC_FVMFILE 0x9 /* fixed VM file inclusion (internal use) */
#defineLC_PREPAGE 0xa /* prepage command (internal use) */
#defineLC_DYSYMTAB 0xb /* dynamic link-edit symbol table info */
#defineLC_LOAD_DYLIB 0xc /* load a dynamicly linked shared library */
#defineLC_ID_DYLIB 0xd /* dynamicly linked shared lib identification */
#defineLC_LOAD_DYLINKER 0xe /* load a dynamic linker */
#defineLC_ID_DYLINKER 0xf /* dynamic linker identification */
#defineLC_PREBOUND_DYLIB 0x10 /* modules prebound for a dynamicly *//* linked shared library *//*
* A variable length string in a load command is represented by an lc_str
* union. The strings are stored just after the load command structure and
* the offset is from the start of the load command structure. The size
* of the string is reflected in the cmdsize field of the load command.
* Once again any padded bytes to bring the cmdsize field to a multiple
* of sizeof(long) must be zero.
*/union lc_str {
unsignedlong offset; /* offset to the string */char *ptr; /* pointer to the string */
};
/*
* The segment load command indicates that a part of this file is to be
* mapped into the task's address space. The size of this segment in memory,
* vmsize, maybe equal to or larger than the amount to map from this file,
* filesize. The file is mapped starting at fileoff to the beginning of
* the segment in memory, vmaddr. The rest of the memory of the segment,
* if any, is allocated zero fill on demand. The segment's maximum virtual
* memory protection and initial virtual memory protection are specified
* by the maxprot and initprot fields. If the segment has sections then the
* section structures directly follow the segment command and their size is
* reflected in cmdsize.
*/struct segment_command {
unsignedlong cmd; /* LC_SEGMENT */unsignedlong cmdsize; /* includes sizeof section structs */char segname[16]; /* segment name */unsignedlong vmaddr; /* memory address of this segment */unsignedlong vmsize; /* memory size of this segment */unsignedlong fileoff; /* file offset of this segment */unsignedlong filesize; /* amount to map from the file */
vm_prot_t maxprot; /* maximum VM protection */
vm_prot_t initprot; /* initial VM protection */unsignedlong nsects; /* number of sections in segment */unsignedlong flags; /* flags */
};
/* Constants for the flags field of the segment_command */
#defineSG_HIGHVM 0x1 /* the file contents for this segment is for
the high part of the VM space, the low part
is zero filled (for stacks in core files) */
#defineSG_FVMLIB 0x2 /* this segment is the VM that is allocated by
a fixed VM library, for overlap checking in
the link editor */
#defineSG_NORELOC 0x4 /* this segment has nothing that was relocated
in it and nothing relocated to it, that is
it maybe safely replaced without relocation*//*
* A segment is made up of zero or more sections. Non-MH_OBJECT files have
* all of their segments with the proper sections in each, and padded to the
* specified segment alignment when produced by the link editor. The first
* segment of a MH_EXECUTE and MH_FVMLIB format file contains the mach_header
* and load commands of the object file before it's first section. The zero
* fill sections are always last in their segment (in all formats). This
* allows the zeroed segment padding to be mapped into memory where zero fill
* sections might be.
*
* The MH_OBJECT format has all of it's sections in one segment for
* compactness. There is no padding to a specified segment boundary and the
* mach_header and load commands are not part of the segment.
*
* Sections with the same section name, sectname, going into the same segment,
* segname, are combined by the link editor. The resulting section is aligned
* to the maximum alignment of the combined sections and is the new section's
* alignment. The combined sections are aligned to their original alignment in
* the combined section. Any padded bytes to get the specified alignment are
* zeroed.
*
* The format of the relocation entries referenced by the reloff and nreloc
* fields of the section structure for mach object files is described in the
* header file <reloc.h>.
*/struct section {
char sectname[16]; /* name of this section */char segname[16]; /* segment this section goes in */unsignedlong addr; /* memory address of this section */unsignedlong size; /* size in bytes of this section */unsignedlong offset; /* file offset of this section */unsignedlong align; /* section alignment (power of 2) */unsignedlong reloff; /* file offset of relocation entries */unsignedlong nreloc; /* number of relocation entries */unsignedlong flags; /* flags (section type and attributes)*/unsignedlong reserved1; /* reserved */unsignedlong reserved2; /* reserved */
};
/*
* The flags field of a section structure is separated into two parts a section
* type and section attributes. The section types are mutually exclusive (it
* can only have one type) but the section attributes are not (it may have more
* than one attribute).
*/
#defineSECTION_TYPE 0x000000ff /* 256 section types */
#defineSECTION_ATTRIBUTES 0xffffff00 /* 24 section attributes *//* Constants for the type of a section */
#defineS_REGULAR 0x0 /* regular section */
#defineS_ZEROFILL 0x1 /* zero fill on demand section */
#defineS_CSTRING_LITERALS 0x2 /* section with only literal C strings*/
#defineS_4BYTE_LITERALS 0x3 /* section with only 4 byte literals */
#defineS_8BYTE_LITERALS 0x4 /* section with only 8 byte literals */
#defineS_LITERAL_POINTERS 0x5 /* section with only pointers to *//* literals *//*
* For the two types of symbol pointers sections and the symbol stubs section
* they have indirect symbol table entries. For each of the entries in the
* section the indirect symbol table entries, in corresponding order in the
* indirect symbol table, start at the index stored in the reserved1 field
* of the section structure. Since the indirect symbol table entries
* correspond to the entries in the section the number of indirect symbol table
* entries is inferred from the size of the section divided by the size of the
* entries in the section. For symbol pointers sections the size of the entries
* in the section is 4 bytes and for symbol stubs sections the byte size of the
* stubs is stored in the reserved2 field of the section structure.
*/
#defineS_NON_LAZY_SYMBOL_POINTERS 0x6 /* section with only non-lazy
symbol pointers */
#defineS_LAZY_SYMBOL_POINTERS 0x7 /* section with only lazy symbol
pointers */
#defineS_SYMBOL_STUBS 0x8 /* section with only symbol
stubs, byte size of stub in
the reserved2 field */
#defineS_MOD_INIT_FUNC_POINTERS 0x9 /* section with only function
pointers for initialization*//*
* Constants for the section attributes part of the flags field of a section
* structure.
*/
#defineSECTION_ATTRIBUTES_USR 0xff000000 /* User setable attributes */
#defineS_ATTR_PURE_INSTRUCTIONS 0x80000000 /* section contains only true
machine instructions */
#defineSECTION_ATTRIBUTES_SYS 0x00ffff00 /* system setable attributes */
#defineS_ATTR_SOME_INSTRUCTIONS 0x00000400 /* section contains some
machine instructions */
#defineS_ATTR_EXT_RELOC 0x00000200 /* section has external
relocation entries */
#defineS_ATTR_LOC_RELOC 0x00000100 /* section has local
relocation entries *//*
* The names of segments and sections in them are mostly meaningless to the
* link-editor. But there are few things to support traditional UNIX
* executables that require the link-editor and assembler to use some names
* agreed upon by convention.
*
* The initial protection of the "__TEXT" segment has write protection turned
* off (not writeable).
*
* The link-editor will allocate common symbols at the end of the "__common"
* section in the "__DATA" segment. It will create the section and segment
* if needed.
*//* The currently known segment names and the section names in those segments */
#defineSEG_PAGEZERO"__PAGEZERO"/* the pagezero segment which has no *//* protections and catches NULL *//* references for MH_EXECUTE files */
#defineSEG_TEXT"__TEXT"/* the tradition UNIX text segment */
#defineSECT_TEXT"__text"/* the real text part of the text *//* section no headers, and no padding */
#defineSECT_FVMLIB_INIT0"__fvmlib_init0"/* the fvmlib initialization *//* section */
#defineSECT_FVMLIB_INIT1"__fvmlib_init1"/* the section following the *//* fvmlib initialization *//* section */
#defineSEG_DATA"__DATA"/* the tradition UNIX data segment */
#defineSECT_DATA"__data"/* the real initialized data section *//* no padding, no bss overlap */
#defineSECT_BSS"__bss"/* the real uninitialized data section*//* no padding */
#defineSECT_COMMON"__common"/* the section common symbols are *//* allocated in by the link editor */
#defineSEG_OBJC"__OBJC"/* objective-C runtime segment */
#defineSECT_OBJC_SYMBOLS"__symbol_table"/* symbol table */
#defineSECT_OBJC_MODULES"__module_info"/* module information */
#defineSECT_OBJC_STRINGS"__selector_strs"/* string table */
#defineSECT_OBJC_REFS"__selector_refs"/* string table */
#defineSEG_ICON"__ICON"/* the NeXT icon segment */
#defineSECT_ICON_HEADER"__header"/* the icon headers */
#defineSECT_ICON_TIFF"__tiff"/* the icons in tiff format */
#defineSEG_LINKEDIT"__LINKEDIT"/* the segment containing all structs *//* created and maintained by the link *//* editor. Created with -seglinkedit *//* option to ld(1) for MH_EXECUTE and *//* FVMLIB file types only */
#defineSEG_UNIXSTACK"__UNIXSTACK"/* the unix stack segment *//*
* Fixed virtual memory shared libraries are identified by two things. The
* target pathname (the name of the library as found for execution), and the
* minor version number. The address of where the headers are loaded is in
* header_addr.
*/struct fvmlib {
union lc_str name; /* library's target pathname */unsignedlong minor_version; /* library's minor version number */unsignedlong header_addr; /* library's header address */
};
/*
* A fixed virtual shared library (filetype == MH_FVMLIB in the mach header)
* contains a fvmlib_command (cmd == LC_IDFVMLIB) to identify the library.
* An object that uses a fixed virtual shared library also contains a
* fvmlib_command (cmd == LC_LOADFVMLIB) for each library it uses.
*/struct fvmlib_command {
unsignedlong cmd; /* LC_IDFVMLIB or LC_LOADFVMLIB */unsignedlong cmdsize; /* includes pathname string */struct fvmlib fvmlib; /* the library identification */
};
/*
* Dynamicly linked shared libraries are identified by two things. The
* pathname (the name of the library as found for execution), and the
* compatibility version number. The pathname must match and the compatibility
* number in the user of the library must be greater than or equal to the
* library being used. The time stamp is used to record the time a library was
* built and copied into user so it can be use to determined if the library used
* at runtime is exactly the same as used to built the program.
*/struct dylib {
union lc_str name; /* library's path name */unsignedlong timestamp; /* library's build time stamp */unsignedlong current_version; /* library's current version number */unsignedlong compatibility_version;/* library's compatibility vers number*/
};
/*
* A dynamicly linked shared library (filetype == MH_DYLIB in the mach header)
* contains a dylib_command (cmd == LC_ID_DYLIB) to identify the library.
* An object that uses a dynamicly linked shared library also contains a
* dylib_command (cmd == LC_LOAD_DYLIB) for each library it uses.
*/struct dylib_command {
unsignedlong cmd; /* LC_ID_DYLIB or LC_LOAD_DYLIB */unsignedlong cmdsize; /* includes pathname string */struct dylib dylib; /* the library identification */
};
/*
* A program (filetype == MH_EXECUTE) or bundle (filetype == MH_BUNDLE) that is
* prebound to it's dynamic libraries has one of these for each library that
* the static linker used in prebinding. It contains a bit vector for the
* modules in the library. The bits indicate which modules are bound (1) and
* which are not (0) from the library. The bit for module 0 is the low bit
* of the first byte. So the bit for the Nth module is:
* (linked_modules[N/8] >> N%8) & 1
*/struct prebound_dylib_command {
unsignedlong cmd; /* LC_PREBOUND_DYLIB */unsignedlong cmdsize; /* includes strings */union lc_str name; /* library's path name */unsignedlong nmodules; /* number of modules in library */union lc_str linked_modules; /* bit vector of linked modules */
};
/*
* A program that uses a dynamic linker contains a dylinker_command to identify
* the name of the dynamic linker (LC_LOAD_DYLINKER). And a dynamic linker
* contains a dylinker_command to identify the dynamic linker (LC_ID_DYLINKER).
* A file can have at most one of these.
*/struct dylinker_command {
unsignedlong cmd; /* LC_ID_DYLINKER or LC_LOAD_DYLINKER */unsignedlong cmdsize; /* includes pathname string */union lc_str name; /* dynamic linker's path name */
};
/*
* Thread commands contain machine-specific data structures suitable for
* use in the thread state primitives. The machine specific data structures
* follow the struct thread_command as follows.
* Each flavor of machine specific data structure is preceded by an unsigned
* long constant for the flavor of that data structure, an unsigned long
* that is the count of longs of the size of the state data structure and then
* the state data structure follows. This triple may be repeated for many
* flavors. The constants for the flavors, counts and state data structure
* definitions are expected to be in the header file <machine/thread_status.h>.
* These machine specific data structures sizes must be multiples of
* sizeof(long). The cmdsize reflects the total size of the thread_command
* and all of the sizes of the constants for the flavors, counts and state
* data structures.
*
* For executable objects that are unix processes there will be one
* thread_command (cmd == LC_UNIXTHREAD) created for it by the link-editor.
* This is the same as a LC_THREAD, except that a stack is automatically
* created (based on the shell's limit for the stack size). Command arguments
* and environment variables are copied onto that stack.
*/struct thread_command {
unsignedlong cmd; /* LC_THREAD or LC_UNIXTHREAD */unsignedlong cmdsize; /* total size of this command *//* unsigned long flavor flavor of thread state *//* unsigned long count count of longs in thread state *//* struct XXX_thread_state state thread state for this flavor *//* ... */
};
/*
* The symtab_command contains the offsets and sizes of the link-edit 4.3BSD
* "stab" style symbol table information as described in the header files
* <nlist.h> and <stab.h>.
*/struct symtab_command {
unsignedlong cmd; /* LC_SYMTAB */unsignedlong cmdsize; /* sizeof(struct symtab_command) */unsignedlong symoff; /* symbol table offset */unsignedlong nsyms; /* number of symbol table entries */unsignedlong stroff; /* string table offset */unsignedlong strsize; /* string table size in bytes */
};
/*
* This is the second set of the symbolic information which is used to support
* the data structures for the dynamicly link editor.
*
* The original set of symbolic information in the symtab_command which contains
* the symbol and string tables must also be present when this load command is
* present. When this load command is present the symbol table is organized
* into three groups of symbols:
* local symbols (static and debugging symbols) - grouped by module
* defined external symbols - grouped by module (sorted by name if not lib)
* undefined external symbols (sorted by name)
* In this load command there are offsets and counts to each of the three groups
* of symbols.
*
* This load command contains a the offsets and sizes of the following new
* symbolic information tables:
* table of contents
* module table
* reference symbol table
* indirect symbol table
* The first three tables above (the table of contents, module table and
* reference symbol table) are only present if the file is a dynamicly linked
* shared library. For executable and object modules, which are files
* containing only one module, the information that would be in these three
* tables is determined as follows:
* table of contents - the defined external symbols are sorted by name
* module table - the file contains only one module so everything in the
* file is part of the module.
* reference symbol table - is the defined and undefined external symbols
*
* For dynamicly linked shared library files this load command also contains
* offsets and sizes to the pool of relocation entries for all sections
* separated into two groups:
* external relocation entries
* local relocation entries
* For executable and object modules the relocation entries continue to hang
* off the section structures.
*/struct dysymtab_command {
unsignedlong cmd; /* LC_DYSYMTAB */unsignedlong cmdsize; /* sizeof(struct dysymtab_command) *//*
* The symbols indicated by symoff and nsyms of the LC_SYMTAB load command
* are grouped into the following three groups:
* local symbols (further grouped by the module they are from)
* defined external symbols (further grouped by the module they are from)
* undefined symbols
*
* The local symbols are used only for debugging. The dynamic binding
* process may have to use them to indicate to the debugger the local
* symbols for a module that is being bound.
*
* The last two groups are used by the dynamic binding process to do the
* binding (indirectly through the module table and the reference symbol
* table when this is a dynamicly linked shared library file).
*/unsignedlong ilocalsym; /* index to local symbols */unsignedlong nlocalsym; /* number of local symbols */unsignedlong iextdefsym; /* index to externally defined symbols */unsignedlong nextdefsym; /* number of externally defined symbols */unsignedlong iundefsym; /* index to undefined symbols */unsignedlong nundefsym; /* number of undefined symbols *//*
* For the for the dynamic binding process to find which module a symbol
* is defined in the table of contents is used (analogous to the ranlib
* structure in an archive) which maps defined external symbols to modules
* they are defined in. This exists only in a dynamicly linked shared
* library file. For executable and object modules the defined external
* symbols are sorted by name and is use as the table of contents.
*/unsignedlong tocoff; /* file offset to table of contents */unsignedlong ntoc; /* number of entries in table of contents *//*
* To support dynamic binding of "modules" (whole object files) the symbol
* table must reflect the modules that the file was created from. This is
* done by having a module table that has indexes and counts into the merged
* tables for each module. The module structure that these two entries
* refer to is described below. This exists only in a dynamicly linked
* shared library file. For executable and object modules the file only
* contains one module so everything in the file belongs to the module.
*/unsignedlong modtaboff; /* file offset to module table */unsignedlong nmodtab; /* number of module table entries *//*
* To support dynamic module binding the module structure for each module
* indicates the external references (defined and undefined) each module
* makes. For each module there is an offset and a count into the
* reference symbol table for the symbols that the module references.
* This exists only in a dynamicly linked shared library file. For
* executable and object modules the defined external symbols and the
* undefined external symbols indicates the external references.
*/unsignedlong extrefsymoff; /* offset to referenced symbol table */unsignedlong nextrefsyms; /* number of referenced symbol table entries *//*
* The sections that contain "symbol pointers" and "routine stubs" have
* indexes and (implied counts based on the size of the section and fixed
* size of the entry) into the "indirect symbol" table for each pointer
* and stub. For every section of these two types the index into the
* indirect symbol table is stored in the section header in the field
* reserved1. An indirect symbol table entry is simply a 32bit index into
* the symbol table to the symbol that the pointer or stub is referring to.
* The indirect symbol table is ordered to match the entries in the section.
*/unsignedlong indirectsymoff; /* file offset to the indirect symbol table */unsignedlong nindirectsyms; /* number of indirect symbol table entries *//*
* To support relocating an individual module in a library file quickly the
* external relocation entries for each module in the library need to be
* accessed efficiently. Since the relocation entries can't be accessed
* through the section headers for a library file they are separated into
* groups of local and external entries further grouped by module. In this
* case the presents of this load command who's extreloff, nextrel,
* locreloff and nlocrel fields are non-zero indicates that the relocation
* entries of non-merged sections are not referenced through the section
* structures (and the reloff and nreloc fields in the section headers are
* set to zero).
*
* Since the relocation entries are not accessed through the section headers
* this requires the r_address field to be something other than a section
* offset to identify the item to be relocated. In this case r_address is
* set to the offset from the vmaddr of the first LC_SEGMENT command.
*
* The relocation entries are grouped by module and the module table
* entries have indexes and counts into them for the group of external
* relocation entries for that the module.
*
* For sections that are merged across modules there must not be any
* remaining external relocation entries for them (for merged sections
* remaining relocation entries must be local).
*/unsignedlong extreloff; /* offset to external relocation entries */unsignedlong nextrel; /* number of external relocation entries *//*
* All the local relocation entries are grouped together (they are not
* grouped by their module since they are only used if the object is moved
* from it staticly link edited address).
*/unsignedlong locreloff; /* offset to local relocation entries */unsignedlong nlocrel; /* number of local relocation entries */
};
/*
* An indirect symbol table entry is simply a 32bit index into the symbol table
* to the symbol that the pointer or stub is refering to. Unless it is for a
* non-lazy symbol pointer section for a defined symbol which strip(1) as
* removed. In which case it has the value INDIRECT_SYMBOL_LOCAL. If the
* symbol was also absolute INDIRECT_SYMBOL_ABS is or'ed with that.
*/
#defineINDIRECT_SYMBOL_LOCAL 0x80000000
#defineINDIRECT_SYMBOL_ABS 0x40000000
/* a table of contents entry */struct dylib_table_of_contents {
unsignedlong symbol_index; /* the defined external symbol
(index into the symbol table) */unsignedlong module_index; /* index into the module table this symbol
is defined in */
};
/* a module table entry */struct dylib_module {
unsignedlong module_name; /* the module name (index into string table) */unsignedlong iextdefsym; /* index into externally defined symbols */unsignedlong nextdefsym; /* number of externally defined symbols */unsignedlong irefsym; /* index into reference symbol table */unsignedlong nrefsym; /* number of reference symbol table entries */unsignedlong ilocalsym; /* index into symbols for local symbols */unsignedlong nlocalsym; /* number of local symbols */unsignedlong iextrel; /* index into external relocation entries */unsignedlong nextrel; /* number of external relocation entries */unsignedlong iinit; /* index into the init section */unsignedlong ninit; /* number of init section entries */unsignedlong/* for this module address of the start of */
objc_module_info_addr; /* the (__OBJC,__module_info) section */unsignedlong/* for this module size of */
objc_module_info_size; /* the (__OBJC,__module_info) section */
};
/*
* The entries in the reference symbol table are used when loading the module
* (both by the static and dynamic link editors) and if the module is unloaded
* or replaced. Therefore all external symbols (defined and undefined) are
* listed in the module's reference table. The flags describe the type of
* reference that is being made. The constants for the flags are defined in
* <mach-o/nlist.h> as they are also used for symbol table entries.
*/struct dylib_reference {
unsignedlong isym:24, /* index into the symbol table */flags:8; /* flags to indicate the type of reference */
};
/*
* The symseg_command contains the offset and size of the GNU style
* symbol table information as described in the header file <symseg.h>.
* The symbol roots of the symbol segments must also be aligned properly
* in the file. So the requirement of keeping the offsets aligned to a
* multiple of a sizeof(long) translates to the length field of the symbol
* roots also being a multiple of a long. Also the padding must again be
* zeroed. (THIS IS OBSOLETE and no longer supported).
*/struct symseg_command {
unsignedlong cmd; /* LC_SYMSEG */unsignedlong cmdsize; /* sizeof(struct symseg_command) */unsignedlong offset; /* symbol segment offset */unsignedlong size; /* symbol segment size in bytes */
};
/*
* The ident_command contains a free format string table following the
* ident_command structure. The strings are null terminated and the size of
* the command is padded out with zero bytes to a multiple of sizeof(long).
* (THIS IS OBSOLETE and no longer supported).
*/struct ident_command {
unsignedlong cmd; /* LC_IDENT */unsignedlong cmdsize; /* strings that follow this command */
};
/*
* The fvmfile_command contains a reference to a file to be loaded at the
* specified virtual address. (Presently, this command is reserved for NeXT
* internal use. The kernel ignores this command when loading a program into
* memory).
*/struct fvmfile_command {
unsignedlong cmd; /* LC_FVMFILE */unsignedlong cmdsize; /* includes pathname string */union lc_str name; /* files pathname */unsignedlong header_addr; /* files virtual address */
};
#endif/*_MACHO_LOADER_H_*/